Blue dye and process of making same.



FETCH.

RENE BOHN, OF MANNHEIM, GERMANY, ASSIGNOR TO BADISCHE ANILIN dz SODA FABRIK, OF LUDXVIGSHAFEN, GERMANY.

BLUE DYE AND PROCESS OF MAKING SAME.

SPECIFICATION forming part of Letters Patent No. 682,523, dated September 10, 1901.

Application filed February 25, 1901. Serial No. 48,792. (No specimens.)

To all whom it may Ww rrw nitrobenzene in blue bronzy needles, which Be it known that I, RENE BOHN, doctor of are similar to indigo in appearance and subphilosophy and chemist, a citizen of the Swiss lime without melting. Republic,residingatMannheim, in the Grand The following examples will serve to illus- 5 Duchy of Baden, Germany, have invented trate the nature of my invention and the new and useful Improvements in Blue Dyes manner in which the same maybe carried and Processes of Making Same, of which the into practical effect; but the invention is not following is a specification. confined to the examples. The parts are by I have discovered that by melting betaweight. 1o amido-anthraquinone with caustic potash at Example1Proclucti0n of blue (lye.Heat

a temperature of one hundred and eighty together ten (10) parts of beta-amido-anthra- (180) to three hundred (300) degrees centiquinone and live hundred (500) parts of solid grade a leuco substance of a new dyestufi is caustic potash forhalf an hour, while stirring formed. On treating the melt thus obtained well, to a temperature of two hundred and 15 with water and blowingin air this leuco subfifty (250) degrees centigrade. \Vhen cold, stance is oxidized and ablue crystalline subpour the melt into water and boil up in the stance separates out in the insoluble form, presence of air. My new coloring-matter which is the new coloring-matter I wish to separates out. Filter it off and wash thorclaim. The same coloring-matter can be oboughly with water. It can be directly em- 2o tained when in place of beta-amido-anthraployed for dyeing after having formed a vat quinone its sulfo-acid or hydrogenized detherefrom bysuitable reduction,as explained rivatives of these substances are melted with in the following example. caustic potash. Example 2 Concersion of blue dye into its My new coloringmatter is insoluble in soluble f0rm.-Suspend one (1) part of my 2 5 caustic-soda or sodium-carbonate solution or new coloring-matter in the form of a paste in dilute hydrochloric-acid solution. It is solufive hundred (500) to one thousand (1,000) ble in nitrobenzene and difticultly soluble in parts of water at a temperature of fifty (50) anilin and chloroform, the solutions being to sixty (60) degrees centigrade. Add twenty blue-green, while it is almost insoluble in (20) to thirty (30) parts by volume of a so- 3o benzene and acetin. In concentrated sulfudium-hydrosulfite solution (containing about ric acid (containing ninety-six per cent. of ten per cent. of sodium hydrosulfite) and ten H 80 it dissolves with a yellow-brown color, (10) to fifteen (15) parts of caustic soda-lye, and in fuming sulfuric acid (containing (containing about twenty-four per cent. of twenty-three per cent. of S0 with a dirty- NaOH.) In about half an hour the coloring- 5 brown color. My new coloring-matter is, matter will have dissolved and the solution however, soluble in caustic-soda solution in directly dyes cotton exceedingly fast blue the form of its leuco compound, which may shades. be obtained by treating the coloring-matter Now what I claim is with a suitable alkaline reducing agent-for 1. The process of producing a new blue 4o example, sodium hydrosulfite in the presdye by melting a hereinbefore-defined betaence of caustic soda-and in this form it examido-anthraquinone substance with caustic hibits the typical properties of a vat, dyeing potash and dissolving the melt in water in the textile fiber, especially cotton, blue shades presence of air, substantially as described. of great brilliancy and excellent fastness. 2. The process of producing a new bluedye 5 5 By oxidizing my new coloring-matter with, by melting a hereinbefore defined betasay, chromic acid it can be converted into a amido-anthraquinone substance with caustic yellow substance, which on suitable reducpotash substantially as described.

tion with sodium hydrosulfite in alkaline so- 3. The new blue dye which can be obtained lution is reconverted into my blue coloringby melting betaamido-anthraquinone with 50 matter. caustic potash and dissolving the melt in wa- My new coloringmatter crystallizes from ter in the presence of air which in its unre duced form is a blue substance insoluble in water and caustic-soda solution, whose solution in concentrated sulfuric acid is yellowbrown, which can be converted by oxidation with chromic acid into a yellow substance which substance is reconverted into the original blue coloring-matter on suitable reduc tion, and which in its reduced form is soluble in caustic-soda solution, which solution dyes textile fiber, especially cotton, directly 10 blue shades, substantially as described.

In testimony whereof I have hereunto set my hand in the presence of two subscribing witnesses. A

RENE BOHN Witnesses:

ROBERT I-IoLDMANN, J OHN L. HEINKE; 

